Rockbox

The encoders for both AIFF and WAV produce the incorrect encoding when the channel mode is set to mono on my Sansa e200 (and probably all other little-endian players) in Rockbox Version 3.3 as well as the latest revision as of this writing (r21985). The problem occurs when recording either from the mic or from FM radio, and with any mono mode (L, R, L+R).

For AIFF, the encoder outputs the incorrect endian-ness of samples, producing files that sound very much like static. For WAV, the encoder swaps samples in pairs, which essentially adds in sawtooth-like waveforms to a smooth input wave. For example, if you have the input sample values 0 1 2 3 4 5, the WAV encoder would output 1 0 3 2 5 4 instead.

I attached a patch which I believe fixes both of these issues for machines of all byte orders. I tested it on the e200 (little endian), but I don’t have any big-endian players to test it on.